Fusion cage

ABSTRACT

A system comprising a fusion cage and at least one engagement member is provided. The fusion cage includes a first member and a second member. The engagement member is configured to retain the first and second members in an expanded state while simultaneously fixing the fusion case to adjacent vertebrae.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and incorporates herein byreference in its entirety:

-   -   Prior U.S. Provisional Patent Application No. 61/777,666 filed        Mar. 12, 2013, and is entitled FUSION CAGE.

BACKGROUND

1. Technical Field

The present disclosure relates to orthopedic implants. Morespecifically, but not exclusively, the present disclosure relates tofusion cages placed between adjacent vertebral bodies at any spinallevel.

2. The Relevant Technology

It is desirable to insert a fusion cage into a patient's body such thatthe fusion cage defines a small footprint during insertion. The fusioncage may be expanded to define a larger footprint or greater height onceit is placed between the vertebral bodies. Fusion cages are often fixedto neighboring bone.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be discussed withreference to the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope.

FIG. 1 is a front view of system 100;

FIG. 1A is a isometric view of a first member;

FIG. 1B is a front view of the first member of FIG. 1A;

FIG. 1C is bottom view of the first member of FIG. 1A;

FIG. 1D is a perspective view of the first member of FIG. 1A;

FIG. 1E is a bottom view of a second member;

FIG. 1F is isometric view of the second member of FIG. 1E;

FIG. 1G is a front view of the second member of FIG. 1E;

FIG. 1H is another view of the second member of FIG. 1E;

FIG. 1I is an isometric view of a collapsed position of system 100;

FIG. 1J is an isometric view of an expanded position of system 100;

FIG. 1K is front view of a collapsed position of system 100 of FIG. 1I;

FIG. 1L is a back view of an expanded position of system 100 of FIG. 1J;

FIG. 2 is a isometric view of system 200;

FIG. 2A is an isometric view of a first member of system 200;

FIG. 2B is a bottom view of the first member of FIG. 2A;

FIG. 2C is a bottom view of a second member of system 200;

FIG. 2D is the top view of the second member of FIG. 2C;

FIG. 2E is an isometric view of an engagement member of system 200;

FIG. 2F is an isometric view of a second engagement member of system200;

FIG. 2G is a front view of a collapsed position of system 200;

FIG. 2H is an isometric view of the collapsed position of FIG. 2G;

FIG. 2I is an isometric view of an expanded position of system 200;

FIG. 3A is an isometric view of a first member of system 300;

FIG. 3B is an isometric view of a second member of system 300;

FIG. 3C is an isometric view of an engagement member;

FIG. 3D is an isometric view of a second engagement member;

FIG. 3E is an isometric view of a collapsed position of system 300;

FIG. 3F is an isometric view of an expanded position of system 300;

FIG. 4A is a front view of a collapsed position of system 400;

FIG. 4B is a front view of an expanded position of system 400;

FIG. 5A is a front view of a collapsed position of system 500;

FIG. 5B is a front view of an expanded position of system 500;

FIG. 6A is a collapsed cross section view of system 600;

FIG. 6B is an expanded view of system 600;

FIG. 6C is an expanded view with an engagement member of system 600;

FIG. 7 is a superior view of system 700;

FIG. 8 is a front view of a system 800;

FIG. 9 is a front view of system 900;

FIG. 10 is a superior view of system 1000;

FIG. 11 is a front view of the system 1000 of FIG. 10;

FIG. 12A is a front view of a collapsed position of system 1200;

FIG. 12B is a front view of an expanded position of system 1200;

FIG. 13 is an anterior view of system 1300;

FIG. 14A is a front view of a collapsed position of system 1400;

FIG. 14B is front view of an expanded position of system 1400; and

FIG. 15 is a front view of system 1500.

DETAILED DESCRIPTION

The present invention relates to fusion cages placed into the spine atany spinal level. The systems and methods described herein may bereadily adapted for other medical devices. The following descriptionillustrates the principles of the invention, which may be applied invarious ways to provide many different alternative embodiments. Thisdescription is not meant to limit the inventive concepts in the appendedclaims. The disclosure may relate to fusion cages employed in spinalfusion procedures. The following description illustrates principles,which may be applied in various ways to provide many differentalternative embodiments. This description is not meant to limit theinventive concepts in the appended claims.

The present technology may be employed in spinal fusion procedureswherein two vertebral bodies are joined together to maintain foraminalheight by replacing the spinal disc whenever required and implanting thefusion cages between the vertebral bodies. While exemplary embodimentsof the present technology have been shown and described in detail below,it will be clear to the person skilled in the art that changes andmodifications may be made without departing from its scope. As such,that which is set forth in the following description and accompanyingdrawings is offered by way of illustration only and not as a limitation.In addition, one of ordinary skill in the art will appreciate uponreading and understanding this disclosure that other variations for thetechnology described herein can be included within the scope of thepresent technology.

Standard medical planes of reference and descriptive terminology areemployed in this specification. A sagittal plane divides a body intoright and left portions. A mid-sagittal plane divides the body intoequal right and left halves. A coronal plane divides a body intoanterior and posterior portions. A transverse plane divides a body intosuperior and inferior portions. Anterior means toward the front of thebody. Posterior means toward the back of the body. Superior means towardthe head. Inferior means toward the feet. Medial means toward themidline of the body. Lateral means away from the midline of the body.Axial means toward a central axis of the body. Abaxial means away from acentral axis of the body.

A system comprising a fusion cage and an engagement member may beprovided between two adjacent vertebral bodies. The fusion cage may bereceived between the two adjacent vertebral bodies in a collapsedposition. Thereafter, the fusion cage may be operated such that thefusion cage assumes an expanded position. The engagement member mayenable the fusion cage to retain the expanded position and or enable thefusion cage to expand.

The fusion cage may be expanded in a superior inferior direction or in afootprint direction. The fusion cage may remain in the collapsedposition before expansion. The fusion cage may be inserted in apatient's body while the fusion cage in the collapsed position.Thereafter, once the fusion cage is located at a position where it mayhave to support two bodies, such as the two adjacent vertebral bodies,the fusion cage may be expanded. Hence, the fusion cage may have asmaller footprint while it is still being located at the desiredlocation, thereby making a fusion cage implant surgery less traumaticfor the patient.

Referring to FIG. 1, a system 100 may be used for providing supportbetween two adjacent vertebral bodies. The system 100 may include afusion cage 102 and an engagement member 104.

The fusion cage 102 may include a first member 106 or first supportmeans and a second member 108 or second support means. The first member106 may be an upper portion or top portion of the fusion cage 102 andthe second member 108 may be a lower portion or bottom portion of thefusion cage 102. On the other hand, the first member 106 may be a lowerportion of the fusion cage 102 and the second member 108 may be an upperportion of the fusion cage 102.

Referring to FIGS. 1A-1D, the first member 106 may include a firstsupport portion 110. The first support portion 110 of the first member106 may interface with at least a surface of a first vertebral body.

The first member 106 may include three support arms 112, 114 and 116.The support arms 112, 114 and 116 may extend from three edges of thefirst support portion 110 of the first member 106. The edges from whichthe support arms 112 and 114 extend may be facing each other. The edgefrom which the support arm 116 extends may be disposed between the edgesfrom which the support arms 112 and 114 extend. The support arms 112,114 extend towards a second support portion from the first supportportion 110.

Each of the support arms may include interface surfaces. The support arm112 may have an interface surface 118, the support arm 114 may have aninterface surface 120 and the support arm 116 may have an interfacesurface 122. The interface surfaces 118, 120 and 122 of the support arms112, 114 and 116 of the first member 106 face away from the firstsupport portion 110.

The support arms 112, 114 and 116 may also include additional surfacesapart from the interface surfaces 118, 120 and 122. Each one of thesupport arms 112 and 114 may include an anterior surface, a posteriorsurface, a surface that interfaces a surface of the first supportportion 110, an external surface and an internal surface.

The support arm 116 may also include additional surfaces. The supportarm 116 may include an anterior surface, a posterior surface, a surfacethat interfaces the first support portion 110 and a surface thatinterfaces with a part of the internal surface of the support arm 112and a surface that interfaces with a part of the internal surface of thesupport arm 114. The surface that interfaces the first support portion110 may be facing away from the interface surface 122.

The internal surface of the support arm 112 of the first member 106 maydefine slots 124. The slots 124 may assume rectangular shape. The slot124 may have a depth in the lateral direction of the support arm 112.The slots 124 may be configured to receive keys.

Similar slots 124 may be included on one of the surfaces of the supportarm 114. Corresponding keys may be present on the support arms of thesecond member 108 which may be received by the slots 124.

The first member 106 may include a first channel 126. The first channel126 may have a configuration such that it can accommodate the engagementmember 104 either partially or entirely within.

The first channel 126 may have an oblique orientation with respect tothe first support portion 110 of the first member 106. The first channel126 may have internal threads partially or entirely throughout thelength of the channel 126.

The first member 106 may further include a step 127. The step 127 may beprovided on the interface surfaces 118, 120 and 122 of the support arms112, 114 and 116 of first support portion 110. The step 127 may beconfigured such that it provides support to the support arms extendingfrom a second support portion from making movement sideward when thefusion cage 102 is in an expanded position.

The steps 127 may assume a rectangular shape extending throughout thelengths of the support arms 112, 114 and 116 and have a width extendingin the inferior direction which may be facing away from the firstsupport portion 110.

Referring to FIGS. 1E-1H, the second member 108 may include a secondsupport portion 128. The second support portion 128 of the second member108 may interface with at least a surface of a second vertebral body.

The second member 108 may include three support arms 130, 132 and 134.The support arms 130, 132 and 134 may extend from three edges of thesecond support portion 128 of the second member 108. The edges fromwhich the support arms 130 and 132 extend may be facing opposite to eachother. The edge from which the support arm 134 extends may be disposedbetween the edges from which the support arms 130 and 132 extend. Thesupport arms 130, 132 and 134 may extend towards the first supportportion 110 from the second support portion 128.

Each of the support arms may include interface surfaces. The support arm130 may have an interface surface 136, the support arm 132 may have aninterface surface 138 and the support arm 134 may have an interfacesurface 140. The interface surfaces 136, 138 and 140 of the support arms130, 132 and 134 of the second member 108 face away from the secondsupport portion 128.

The support arms 120, 122 and 124 may also include additional surfacesapart from the interface surfaces 132, 134 and 136. Each one of thesupport arms 120 and 122 may include an anterior surface, a posteriorsurface, a surface that interfaces a surface of the second supportportion 120, an external surface and an internal surface.

The support arm 124 may also include additional surfaces. The supportarm 124 may include an anterior surface, a posterior surface, a surfacethat interfaces a surface of the second support portion 128 and asurface that interfaces with a part of the internal surface of thesupport arm 120 and another surface that interfaces with a part of theinternal surface of the support arm 122. The surface that interfaces asurface the second support portion 128 may be facing away from theinterface surface 140.

The second member 108 may further include a step 142. The step 142 maybe provided on the interface surfaces 136, 138 and 140 of the supportarms 130, 132 and 134 of the second support portion 128. The step 142may be configured such that it provides support to the support arms 112,114 and 116 from making movement sideward when the fusion cage 102 is inan expanded position.

The steps 142 may assume a rectangular shape extending throughout thelengths of the support arms 130, 132 and 134 and have a width extendingin a superior direction which may be facing away from the second supportportion 128.

The external surface of the support arm 130 of the second member 108 mayinclude keys 144. A key 144 may assume a rectangular shape. The key 144may be a rectangular structure extending externally towards the slot 124present on the support arm 112 of the first member 106 in the lateraldirection of the support arm 130. The key 144 may be configured suchthat the width of the key 144 may be accommodated within the width andthe depth of the slot 124. Similar keys 144 may be included on theexternal surface of the support arm 132.

The second member 108 may include a second channel 146. The secondchannel 146 may have a configuration such that it can accommodate theengagement member 104 either partially or allow the engagement member104 to pass through it.

The second channel 146 may have an oblique orientation with respect tothe second support portion 128 of the second member 108. The secondchannel 146 may have internal threads partially or entirely throughoutthe length of the channel 146.

The engagement member 104 of the system 100 may be configured to providesupport to the first member 106 and the second member 108 in an expandedposition and may retain the expanded position as long as requirementpersists, and may even mechanically engage the fusion cage 102 with thevertebral bodies.

More specifically, the engagement member 104 (or any other engagementmember or similar structure described in this disclosure) may serve toprovide two functions simultaneously: first, engagement with first andsecond expanding members (such as members 106 and 108) in an expandedposition, and second, engagement (or fixation, such as supplementalfixation) with surrounding tissue or bone (such as a vertebral bodyadjacent the fusion cage 102, first member 106, and/or second member108). Since engagement member 104 (or any other engagement member orsimilar structure) fixes the system 100 in an expanded state while alsofixing the system 100 and its associated structures to neighboring bone,the engagement member accomplishes multiple functions with a single (orfew) structure(s). By providing fixation of the system in an expandedstate and fixation of the system to one or more neighboring bones orvertebrae through a single (or few) structure(s), the engagement memberis an improvement over existing systems that otherwise require multiplestructures to provide those multiple functions. The multiple structuresof other systems leave little remaining internal space within the system100 for bone graft, cement, biologic material, or other material to beincluded. By contrast, the current system 100 is an expandable fusioncage having a single engagement member capable of simultaneously lockingthe cage in the expanded state and locking the cage to adjacentvertebral (or other bone) tissue using supplemental fixation, in such amanner as to increase the volume of the void within the cage for theinclusion of bone graft, biologic material, or bone cement. Theinclusion of additional bone graft, biologic material, or bone cementwithin a spinal fusion cage can help promote bone growth and strongerspinal fusion within the space surrounding an implanted cage or system100. Thus, clinical outcomes for patients may be improved by themulti-functional engagement members of the present disclosure.

The engagement member 104 may include threads partially or entirelythroughout the length of the engagement member 104. The engagementmember 104 may be partially or entirely received by the first channel126 and the second channel 146 in the expanded position of the fusioncage 102. The engagement member 104 may be a screw or any other memberwhich may be used to provide support to the fusion cage 102 in itsexpanded position.

The engagement member 104 may be received by the channels 126 and 146 byaligning the threads in the channels 126 and 146 with the threads of theengagement member 104. The alignment of the threads in the channels 126and 146 and the threads of the engagement member 104 ensures securefastening of the engagement member 104 within the channels 126 and 146.

Referring to FIG. 1I, the first support portion 110 may be configuredsuch that in a collapsed position, the support arms 112, 114 and 116extending from the support portion 110 may be disposed between thesupport arms 130, 132 and 134 extending from the second support portion128.

In the collapsed position, the external surface of support arms 112 maycoincide with the internal surface of the support arm 130. The externalsurface of support arm 114 may coincide with the internal surface of thesupport arm 132. The posterior surface of the support arm 116 maycoincide with the anterior surface of the support arm 134. Theconfiguration of the support arms 114, 116, 118 and the support arms130, 132 and 134 in the collapsed position may define a first space 117.

In the collapsed position, slots 124 provided on the external surface ofthe support arm 112 of the first support portion 110 may be received bythe corresponding keys 144 provided on the external surface of thesupport arm 130 of the second support portion 128. The key 144 may beconfigured such that the width of the key 144 may be accommodated withinthe width and the depth of the slot 124. The reception of the keys 144by the slots 124 ensure that, in the collapsed position, the movement ofthe first member 106 and the second member 108 is prevented.

The fusion cage 102 may be operated to assume the expanded position bymoving one of the first member 106 or the second member 108 in asuperior inferior direction. The movement in the superior inferiordirection may occur along the longitudinal axis of the slots and keys144.

While moving the first member 106 or the second member 108 in thesuperior inferior direction, the distance between the first supportportion 110 and the second support portion 128 increases until the keys144 exit the slots 124.

In the expanded position, a portion of one of the interface surface(s)118 of the support arm 112 may interface with interface surface 136 ofthe support arm 130. Similarly, interface surface 120 of the support arm114 may interface with interface surface 138 of the support arm 132, andinterface portion 122 of the support arm 116 may interface withinterface surface 140 of the support arm 134.

Once the keys 144 exit the slots 124 while expanding the fusion cage102, one of the first member 106 or the second member 108 may be movedin a direction orthogonal to the longitudinal axis of the slots 124 andkeys 144. By moving the first member 106 or the second member 108 indirection orthogonal to the longitudinal axis of the slots 124 and keys144, it is ensured that further movement between the first member 106and the second member 108 is prevented in the expanded position.

In the expanded position, the steps 142 provided on the second member108 may receive a portion of the external surfaces of the support arms112 and 114 and a portion of the posterior surface of the support arm116. The reception of the external surfaces of the support arms 112, 114and 116 by the steps 142 may prevent the first member 106 from makingsideward movement in the expanded position.

Referring to FIG. 1J, in the expanded position, the support arms 112,114, 116, 120, 122 and 124, the first support portion 110 and the secondsupport portion 120 define a second space 119. The second space 119 maybe used for insertion of graft material during the spinal fusionprocess.

Referring to FIG. 1K, in the collapsed position, the first channel 126and the second channel 146 may be at offset positions. The offset may beobliquely oriented with respect to the first channel 126 and the secondchannel 146. The offset may further be oriented at a parallel positionwith respect to the first channel 126 and the second channel 146.

Referring to FIG. 1L, in an expanded position, when the first member 106is moved along the longitudinal axis of the slots 124 and keys 144, thefirst channel 144 being a part of the first member 106 and the secondchannel 144 being a part of the second member 108, also move therebymaking an alignment.

In an expanded position, the alignment of the first channel 126 with thesecond channel 146 makes way for the engagement member 104 to bedisposed into the channels 126 and 146. When the engagement member 104is received by the channels 126 and 146, the threads in the channels 126and 146 aligns with the threads of the engagement member 104. Thealignment of the threads in the channels 126 and 146 and the threads ofthe engagement member 104 ensures secure fastening of the engagementmember 104 within the channels 126 and 146.

Referring to FIG. 2, a system 200 may be used for providing support totwo adjacent vertebral bodies. The system 200 may include a fusion cage202 and an engagement member 204.

The fusion cage 202 may include a first member 206 and a second member208. The first member 206 may be an upper portion of the fusion cage 202and the second member 208 may be a lower portion of the fusion cage 202.On the other hand, the first member 206 may be a lower portion of thefusion cage 202 and the second member 208 may be an upper portion of thefusion cage 202.

Referring to FIGS. 2A-2B the first member 206 may include a firstsupport portion 210. The first support portion 210 of the first member206 may interface with at least a surface of a first vertebral body.

The first member 206 may include a pair of support arms 212 and 214. Thesupport arms 212 and 214 may extend from two edges of the first supportportion 210 of the first member 206. The edges from which the supportarms 212 and 214 extend may be facing opposite to each other. Thesupport arms 212 and 214 extend towards the second support portion 208from the first support portion 210.

Each of the support arms may include interface surfaces. The support arm212 may have an interface surface 220 and the support arm 214 may havean interface surface 222. The interface surfaces 220 and 222 of thesupport arms 212 and 214 of the first member 206 face away from thefirst support portion 210.

The support arms 212 and 214 may also include additional surfaces apartfrom the interface surfaces 220 and 222. Each one of the support arms212 and 214 may include an anterior surface, a posterior surface, asurface that interfaces a surface of the first support portion 210, anexternal surface and an internal surface.

The external surface of the support arm 212 may be present on one sideof the support arm 212 and the internal surface the support arm 212 maybe present on the other side of the support arm 212, if viewed from theanterior direction. Similarly, the external surface of the support arm214 may be present on one side of the support arm 214 and the internalsurface the support arm 214 may be present on the other side of thesupport arm 214 if viewed from the anterior direction. The surface thatinterfaces a surface of the first support portion 210 may be facing awayfrom the interface surfaces 220 and 222.

The first member 206 may further include a step 230. The step 230 may beprovided on the interface surfaces 220 and 222. The step 230 may beconfigured such that it provides support to the support arms 212 and 214from making movement sideward when the fusion cage 202 is in an expandedposition.

The step 226 may assume a rectangular shape extending throughout thelengths of the support arms 212 and 214 and have a width extending in aninferior direction which may be facing away from the first supportportion 210.

The external surface of the support arms 212 of the first member 206 mayinclude slots 232. The slot 232 may be a trapezoidal aperture, whenviewed from the anterior and the posterior sides with a depth cuttowards the lateral direction of the support arm 212. The slots 232 maybe configured to receive keys.

Similar slots 232 may be included on the internal surface of the supportarm 214. Corresponding keys may be present on the support arms of thesecond member 208 which may be received by the slots 232.

The first member 206 may include a first channel 236. The first channel236 may have a configuration such that it can accommodate the engagementmember 204 either partially or entirely within the first channel 236.

The first channel 236 may be included on one of the surfaces of thesupport arm 212 of the first supporting portion 210 and may extend to anoffset distance. The first channel 236 may be configured to receive theengagement member 204. The engagement member 204 may be partially orentirely received by the first channel 236.

The first channel 236 may be provided on the anterior surface of thesupport arm 212. The first channel 236 may have an orthogonalorientation with respect to the first support portion 210 of the firstmember 206.

The first channel 236 may further define a first neck member receivingportion 238, a first beam member receiving portion 240 and a beamconnecting member receiving portion 242.

The first neck receiving portion 238 may receive at least a portion of afirst neck member. The first beam member receiving portion 238 mayreceive a portion of a first beam member. The beam connecting memberreceiving portion 240 may receive a first portion of a beam connectingmember.

Referring to FIGS. 2C-2D, the second member 208 may include a secondsupport portion 224. The second support portion 224 of the second member208 may interface with at least a surface of a second vertebral body.

The second member 208 may include a pair of support arms 216 and 218.The support arms 216 and 218 may extend from two edges of the firstsupport portion 224 of the second member 208. The edges from which thesupport arm 216 and 218 extend may be facing opposite to each other. Thesupport arms 216 and 218 extend towards the first support portion 210from the second support portion 224.

Each of the support arms may include one or more interface surfaces. Thesupport arm 216 may have an interface surface 226 and the support arm218 may have an interface surface 228. The interface surfaces 226 and228 of the support arms 216 and 218 of the second member 208 face awayfrom the second support portion 224.

The support arms 216 and 218 may also include additional surfaces apartfrom the interface surfaces 226 and 228. Each one of the support arms216 and 218 may include an anterior surface, a posterior surface, asurface that interfaces the second support portion 224, an externalsurface and an internal surface.

The external surface of the support arm 216 may be present on one sideof the support arm 216 and the internal surface the support arm 216 maybe present on the other side of the support arm 216, if viewed from theanterior direction. Similarly, the external surface of the support arm218 may be present on one side of the support arm 218 and the internalsurface the support arm 218 may be present on the other side of thesupport arm 218 if viewed from the anterior direction. The surface thatinterfaces a surface of the second support portion 224 may be facingaway from the interface surfaces 226 and 228.

The second member 204 may further include a step 250 which may besimilar in structure to the step 230. The step 250 may be provided onthe interface surfaces 226 and 228. The step 250 may assume arectangular shape extending throughout the lengths of the support arms216 and 218 and have a width extending in a direction which may befacing away from the second support portion 224.

The step 230 may be configured such that the step 230 provides supportto the support arms 216 and 218 from making a movement sideward when thefusion cage 202 is in an expanded position. The step 250 may beconfigured such that it provides support to the support arms 212 and 214from making a movement sideward when the fusion cage 202 is in anexpanded position.

The internal surface of the support arms 216 of the second member 208may include keys 234. The key 234 may be a trapezoidal structure, whenviewed from the anterior and the posterior sides with an extensiontowards the slot 232 in the lateral direction of the support arm 214.The keys 234 may be configured to be received by the slots 232. Similarkeys 234 may be included on the external surface of the support arm 218.

The second member 208 may include a second channel 244. The secondchannel 244 may have a configuration such that it can accommodate theengagement member 204 either partially or entirely within the secondchannel 244.

The second channel 244 may be included on one of the surfaces of thesupport arm 216 of the second support portion 224 and may extend to anarbitrary distance in the anterior and posterior direction. The secondchannel 244 may be configured to receive the engagement member 204. Theengagement member 204 may be partially or entirely received by thesecond channel 244.

The second channel 244 may be provided on the anterior surface of thesupport arm 216. The second channel 244 may include the second neckmember receiving portion 246 and second beam member receiving portion248. A portion of the beam connecting member receiving portion 242 maybe included in the second channel 244. The second channel 244 may havean orthogonal orientation with respect to the second support portion 216of the second member 208.

Referring to FIGS. 2E-2F, the engagement member 104 may comprise a firstblade member 252, a first neck member 254, a first beam member 256, asecond beam member 258 and a beam connecting member 260. The engagementmember 204 may also be entirely received by the first channel 236 andthe channel 244.

The first blade member 252 may be inserted into a first vertebral body.The first blade member 252 may have hexagonal structure if viewed fromthe anterior and posterior directions. The hexagonal first blade member252 may have a width extended in the anterior posterior direction.

The first neck member 254 may provide a connection between the firstblade member 252 and the first beam member 256. The first neck member254 provides a support to the fusion cage 202 by connecting it with thefirst blade member 252. The first neck member 254 may have a rectangularbody with a width extending from the anterior direction to the posteriordirection.

The first beam member 256 may also assume a rectangular body with awidth extending from the anterior direction to the posterior direction.The dimension of the first beam member 256 may be bigger than the firstneck member 254.

The second beam member 258 may be positioned such that it is closer tothe second vertebral body and farther from the first vertebral body. Thebeam connecting member 260 connects the first beam member 256 and thesecond beam member 258. The second beam member 258 may have a structurethat resembles the first beam member 256.

The beam connecting member 260 may also have a rectangular body with awidth extending in the anterior posterior direction. The dimension ofthe beam connecting member 260 may be similar to the first neck member254.

The engagement member 254 may additionally have a second neck member 262and a second blade member 264. The second neck member 262 may resemblethe first neck member 254. The second blade member 264 may resemble thefirst blade member 252.

The second blade member 264 may be inserted into the second vertebralbody. The second neck member 262 provides a connection between thesecond blade member 264 and the second beam member 258.

The first member 206 and the second member 208 may include a secondengagement member 268, which resembles the engagement member 204. Forthe second engagement member 268 to be accommodated in the fusion cage202, the first member 206 and the second member 208 may define additionchannels 270 and 272.

Additional channel 270 may be a part of the first member 206 such thatthe additional channel 270 may be included on one of the surfaces of thesupport arm 214 of the first support portion 210 and may resemble thefirst channel 236.

Additional channel 272 may be a part of the second member 208 such thatthe additional channel 272 may be included on one of the surfaces of thesupport arm 218 of the second support portion 224 and may resemble thefirst channel 244.

Referring to FIGS. 2G-2H, the support arms may be configured such thatin a collapsed position, the support arms 212 and 214 extending from thefirst support portion 210 may be disposed into the second supportportion 224 in a direction lateral to the support arms 216 and 218extending from the second support portion 224. The configuration of thesupport arms 212 and 214 and the support arms 216 and 218, in acollapsed position may define a first space 225.

In the expanded position, a portion of one of the interface surfaces ofeach of the support arms of the first member 206 may interface with aportion of the interface surface of the support arms of the secondmember 208. For example, interface surface 220 of the support arm 212interfaces with interface surface 226 of the support arm 216. Similarly,interface surface 222 of the support arm 214 interfaces with interfacesurface 228 of the support arm 218.

The slots 232 of the support arm 212 of the first member 206 may bereceived in the corresponding keys 234 of the support arm 216 of thesecond member 208 in a collapsed state. The reception of the keys 234 bythe slots 232 ensure that, in the collapsed state, the movement of thefirst member 206 and the second member 208 may be prevented.

The first member 206 or the second member 208 may be pushed sidewardsuch that the keys 234 engage into the slots 232. One of the firstmember 206 or the second member 208 may be pushed to an offset positionin the superior inferior direction such that the grip between the key234 and the slot 232 is tightened.

One of the first member 206 or the second member 208 may be pushed to anoffset position in the superior inferior direction such that the gripbetween the key 234 and the slot 232 is loosened by the push. After thepush, the first member 206 or the second member 208 may be movedsideward until the keys 234 are entirely disengaged from the slots 232.Once the keys 234 exit the slots 232, the first member 206 and thesecond member 208 become movable in a superior inferior direction.

The fusion cage 202 may be operated to assume the expanded position bymoving one of the first member 206 or the second member 208 in asuperior inferior direction. The movement in the superior inferiordirection may occur along the longitudinal axis of the slots 232 andkeys 234.

Referring to FIG. 2I, while moving the first member 206 or the secondmember 208 in the superior inferior direction, the distance between thefirst support portion 210 and the second support portion 224 mayincrease thereby defining a second space 227 in the area between thefirst support portion 210, the second support portion 224 and thesupport arms 212, 214, 216 and 218. The empty space may be employed toaccommodate the graft material during the fusion procedures.

Once the fusion cage 202 is expanded, one of the first member 206 or thesecond member 208 may be moved in a direction orthogonal to thelongitudinal axis of the slots 232 and keys 234. By moving the firstmember 206 or the second member 208 in that direction it is ensured thatfurther movement between the first member 206 and the second member 208is prevented in the expanded position.

Upon moving one of the first member 206 or the second member 208 in adirection orthogonal to the longitudinal axis of the slots 232 and keys234, an interface surface 220 coincides with another interface surface226 and interface surface 222 coincides with another interface surface228. Further, additional support is provided to the first member 206 andthe second member 208 by employing steps 230 and steps 250.

In an expanded position, when one of the first member 206 or the secondmember 208 is moved along the longitudinal axis of the slots 232 andkeys 234, the first channel 236 being a part of the first member 206 andthe second channel 244 being a part of the second member 208, also movethereby making an alignment.

In an expanded position, the alignment of the first channel 236 with thesecond channel 244 makes way for the engagement member 104 to bedisposed into the channels 236 and 244.

In an expanded position, the first neck member 254, the first beammember 256 and a part of the beam connecting member 260 may be insertedinto the first channel 236. The second neck member 262, the second beammember 258 and a part of the beam connecting member 260 may be insertedinto the second channel 244.

In an expanded position, the first neck member receiving portion 238 mayreceive the first neck member 254. The beam connecting member receivingportion 242 may receive the beam connecting member 260. The second beammember receiving portion 248 may receive the second beam member 258.

Referring to FIG. 3, a system 300 may include a fusion cage 302 and anengagement member 304. The fusion cage 302 may include a first member306 and a second member 308.

The first member 306 may be an upper portion of the fusion cage 302 andthe second member 308 may be a lower portion of the fusion cage 302. Onthe other hand, the first member 306 may be a lower portion of thefusion cage 302 and the second member 308 may be an upper portion of thefusion cage 302.

Referring to FIG. 3A, the first member 306 may include a first supportportion 310. The first support portion 310 of the first member 306 mayinterface with at least a surface of a first vertebral body.

The first member 306 may also include a support arm 312. The support arm312 may extend from an edge of the first support portion 310 of thefirst member 306. The support arm 312 may extend towards a secondsupport portion from the first support portion 310.

The support arm 312 may include a first interface surface 314. The firstinterface surface 314 may interface with at least a second interfacesurface of the second member 308. The first interface surface 314 mayhave a smaller footprint than the first support portion 310. The firstinterface surface 314 may be facing away from the first support portion310.

A portion of the first member 306 may be folded in a collapsed positionwhich can be expanded from within the second member 308.

A portion of the first member 306 may include a first channel 316disposed at some portion between the first support portion 310 and theinterface surface 314. The first channel 316 may be configured such thatthe first channel 316 accommodates a portion of the engagement member304.

The first channel 316 may be configured such that a portion of it may bedisposed within the first member 306. The first channel 316 may includea depth cut along its length towards the first interface surface 314starting from a portion of the support arm 312. The dimension of the cutmay bay be configured such that it accommodates a portion of theengagement member 304.

Referring to FIG. 3B, the second member 308 may include a second supportportion 318. The second support portion 318 of the second member 308 mayinterface with at least a surface of a first vertebral body.

The second member 308 may also include a support arm 320. The supportarm 320 may extend from an edge of the second support portion 318 of thesecond member 308. The support arm 320 may extend towards the firstsupport portion 310 from the second support portion 318.

The support arm 320 may include a second interface surface 322. Thesecond interface surface 322 may interface with at least the firstinterface surface 314 of the first member 306. The second interfacesurface 322 may have a smaller footprint than the second support portion318. The second interface surface 322 may be facing away from the secondsupport portion 318.

A portion of the second member 308 may be folded in a collapsed positionwhich may be expanded from within the first member 306.

A portion of the second member 308 may include a second channel 324disposed at some portion between the second support portion 318 and theinterface portion 320. The second channel 324 may be configured suchthat the second channel 324 accommodates a portion of the engagementmember 304.

The second channel 324 may be configured such that a part of it may bedisposed within the second member 308. The second channel 324 mayinclude a depth cut along its length towards the second interfaceportion 320 starting from a portion of the connecting surface 322. Thedimension of the cut may be configured such that it accommodates aportion of the engagement member 304.

Referring to FIG. 3C, the engagement member 304 may be a trapezoidalshaped member from one perspective creating a thin tapered insert with afirst surface 326 and a second surface 328. The first surface 326 of theengagement member 304 may be smaller than the second surface 328. Thefirst surface 326 may be inserted first into the channels 316 and 324.The second surface 328 follows the first surface 325 into the channels316 and 324.

The engagement member 304 may include an additional channel 330. Theadditional channel 330 may extend within its body from the secondsurface 328 towards the first surface 326 along an axis 327. The axis327 may extend from the second surface 328 to the first surface 326 inthe lateral direction of the engagement member 304. The additionalchannel 330 may have internal threads partially or entirely throughoutthe length of the additional channel 330.

Referring to FIG. 3D, the system 300 may include a second engagementmember 332. The second engagement member 332 may include a blade 334which may be inserted into the additional channel 330. The blade 334 mayassume a length in the lateral direction.

The blade 334 may extend externally from a blade anchor 336 along anaxis 329. The axis 329 may extend from the blade anchor 336 in thelateral direction. The blade 334 may have an orthogonal orientation withrespect to the blade anchor 336 from which the blade 334 extends.

The blade anchor 336 may assume a length in the superior interiordirection. The blade 334 may be disposed at the midpoint of the bladeanchor 336. The blade anchor 336 may include additional blades disposedat the proximal end and the distal end of the blade anchor 336.

The blade 334 may be configured such that a portion of it may beinserted into at least a portion of the additional channel 330.

A blade 338 may resemble the blade 334 and may extend in the lateraldirection at the proximal end of the blade anchor 336. The blade 338 maybe configured such that a portion of it may be inserted into at least aportion of the first vertebral body.

A blade 340 may resemble the blade 334 and may extend in the lateraldirection at the distal end of the blade anchor 336. The blade 340 maybe configured such that a portion of it may be inserted into the secondvertebral body.

The blades 334, 338 and 340 and the blade anchor 336 may form an Eshaped structure from the anterior direction. The blade 334 may bepositioned relatively half way between the blade 338 and blade 340.

Referring to FIG. 3E, in the collapsed position, a portion of the firstmember 306 or the second member 308 may be folded within the othermember and may be expanded from within the other member.

Referring to FIG. 3F, in the expanded position, the first channel 316and the second channel 324 may define a trapezoidal aperture 325 with adepth which may accommodate the engagement member 304.

The first surface 326 of the engagement member 304 may be inserted firstinto the trapezoidal aperture 325. The second surface 328 follows thefirst surface 325 into the trapezoidal aperture 325. The engagementmember 304 may be received by the trapezoidal aperture 325. Theengagement member 304 may ensure prevention to the first member 306 andthe second member 308 in the expanded position from backing out of theexpanded position.

The second engagement member 332 may provide additional support to thefusion cage 302 to maintain the expanded position. The blade 334 of thesecond engagement member 332 may be inserted into the additional channel330 of the engagement member 304. The blades 338 may be inserted intothe first vertebral body and the blade 340 may be inserted into thesecond vertebral body.

The insertion of the blade 338 into the first vertebral body and theinsertion of the blade 340 into the second vertebral body may ensure asecure fastening of the fusion cage 302 in between the first vertebralbody and the second vertebral body in an expanded position.

Referring to FIG. 4, a system 400 may be used for providing support totwo adjacent vertebral bodies. The system 400 may include a fusion cage402 and an engagement member 404.

Referring to FIGS. 4A-4B, the fusion cage 402 includes a first member406 and a second member 408.

The first member 406 may include a first support portion 410. The firstsupport portion 410 of the first member 406 may interface with at leasta surface of the first vertebral body.

The first member 406 may include a support arm 412. The support arm 412and may extend an edge of the first support portion 410 of the firstmember 406. The support arm 412 may extend towards a second supportportion from the first support portion 410.

The support arm 412 may include an interface surface 414. The interfacesurface 414 may be facing away from the first support portion 410. Theinterface surface may interface at least a surface of the second member408.

The support arm 412 may also include an anterior surface, a posteriorsurface, an external surface, an internal surface and a surface thatjoins the first support portion 410. The internal surface of the supportarm 412 may include slots 416. The slots 416 may assume triangulartoothed structure. The internal surface of the support arm 412 mayinterface at least a portion of the engagement member 404.

The second member 408 may include a second support portion 418. Thefirst second support portion 418 of the second member 408 may interfacewith at least a surface of the second vertebral body.

The second member 408 may include a support arm 420. The support arm 420and may extend from an edge of the second support portion 418 of thesecond member 408. The support arm 420 may extend towards the firstsupport portion 410 from the second support portion 418.

The support arm 420 may include an interface surface 422. The interfacesurface 422 may be facing away from the second support portion 418. Theinterface surface 422 may interface at least a surface of the firstmember 406.

The support arm 420 may also include an anterior surface, a posteriorsurface, an external surface, an internal surface and a surface thatjoins the second support portion 418. The internal surface of thesupport arm 420 may include slots 424. The slots 424 may assumetriangular toothed structure. The internal surface of the support arm420 may interface at least a portion of the engagement member 404.

The engagement member 404 may be a rotational gear positioned betweenthe first support portion 410 and the second support portion 418.

The slots 416 and slots 424 may be facing the rotational gear 404. Theslots 416 and slots 424 provide a ratcheting mechanism to engage therotational gear 404. As the rotational gear 404 is rotated the firstsupport portion 410 and the second support portion 418 may extend awayfrom each other.

In the expanded position, the first support portion 410 interfaces atleast a surface of the first vertebral body and the second supportportion 418 interfaces at least a surface of the second vertebral body.

Referring to FIGS. 5A-5B, a system 500 may be used for providing supportto two adjacent vertebral bodies. The system 500 may include a fusioncage 502 and an engagement member 504. The fusion cage 502 includes afirst member 506 and a second member 508.

The first member 506 may include a first support portion 510. The firstsupport portion 510 of the first member 506 may interface with at leasta surface of the first vertebral body.

The first member 506 may include a pair support arms 512 and 514. Thesupport arms 512 and 514 may extend from two edges of the first supportportion 510 of the first member 506. The support arms 512 and 514 mayextend towards a second support portion from the first support portion510.

Each of the support arms may include interface surfaces. The support arm512 may have an interface surface 516 and the support arm 514 may havean interface surface 518. The interface surfaces 516 and 518 of thesupport arms 512 and 514 of the first member 506 face away from thefirst support portion 510.

The second member 508 may include a second support portion 520. Thesecond support portion 520 of the second member 508 may interface withat least a surface of the first vertebral body.

The second member 508 may include a pair support arms 522 and 524. Thesupport arms 522 and 524 may extend from two edges of the second supportportion 520 of the second member 508. The support arms 522 and 524 mayextend towards the first support portion 510 from the second supportportion 520.

Each of the support arms may include interface surfaces. The support arm522 may have an interface surface 526 and the support arm 524 may havean interface surface 528. The interface surfaces 526 and 528 of thesupport arms 522 and 524 of the second member 508 face away from thesecond support portion 520.

The engagement member 504 may be an oblong shaped cam. The engagementmember 504 may be disposed between the first member 506 and the secondmember 504. A portion of the engagement member 504 at the proximal endinterfaces a surface of the first support portion 510. A portion of theengagement member 504 at the distal end interfaces a surface of thesecond support portion 520.

In the collapsed state, the oblong cam 504 may assume a shape such thatthe diameter of the oblong cam 504 may be extended more along thelateral direction on both sides. Hence the oblong cam 504 may be widerthan it is tall in the collapsed position.

A portion of the first member 506 may partially reside within the secondmember 508, in the collapsed position.

The oblong cam 504 may be actuated such that the oblong cam 504 mayassume a different shape. The oblong cam 504, upon actuation, may assumea shape such that the diameter of the oblong cam 504 may be extendedmore along the superior inferior direction. Hence, in its expanded statethe oblong cam 504 may be taller than it is wide.

The shape of the oblong cam 504 may extend the space between the firstsupport portion 510 and the second support portion 520 thereby expandingthe distance between the first member 506 and the second member 508.

The system 500 may include a second engagement member 530. The secondengagement member 530 may be one or more retractable blades.

The retractable blades 530 may be employed to prevent the oblong cam 504and the fusion cage 502 from sliding back to the collapsed position. Theblades 530 may be retracted when the oblong cam 504 is in its collapsedstate. The blades 530 may be deployed with the same instrument used toactuate the cam 504 and are deployed when the cam 504 is in the expandedposition.

Referring to FIGS. 6A-6C, a system 600 may be used for providing supportto two adjacent vertebral bodies. The system 600 may include a fusioncage 602 and an engagement member 604. The fusion cage 602 includes afirst member 606 and a second member 608.

The first member 606 may include a first support portion. The firstsupport portion of the first member 606 may interface with at least asurface of the first vertebral body.

The first member 606 may include a pair support arm. The support armsmay extend from two edges of the first support portion of the firstmember 606. The support arms may extend towards a second support portionfrom the first support portion.

The internal surface and the external surface of the support arm 612 mayinclude keys 620 and 622. Similarly, the internal surface and theexternal surface of the support arm 614 may include keys 624 and 626.The keys 620, 622, 624 and 626 may include toothed structures. The keys620, 622, 624 and 626 may be received by corresponding slots provided inthe support arms of the second member 608.

The second member 608 may include a second support portion. The secondsupport portion of the second member 608 may interface with at least asurface of the first vertebral body.

The second member 608 may include a pair support arms. The support armsmay extend from two edges of the second support portion of the secondmember 608. The support arms may extend towards the first supportportion 610 from the second support portion 624.

The second member 608 may include slots 638 and 640. The slots 638 and640 may assume toothed structures. The slots 638 and 640 may be presenttwo opposite surface of each of the rectangular apertures. The slots 638may receive the keys 620 and 622 and slots 640 may receive the keys 624and 626.

The keys 620, 622, 624 and 626 are fastened within the slots 638 and 640by means of a ratchet system.

The engagement member 604 may be a locking plate. A second engagementmember may be used in conjunction with the engagement member 604. Thesecond engagement member may include one or more pins. The locking plate604 may extend in an anterior posterior direction. The pins with theplate 604 engage the fusion cage 602 and lock the fusion cage 602 in anexpanded position.

Referring to FIG. 7, a system 700 may include a fusion cage 702 and anengagement member 704. The fusion cage 702 may be shaped like ahorse-shoe or assume a U-shape from the superior direction. At least onesurface of each of the two support arms of the U shape may include anengagement member 704 which may be movable in such a manner to expandthe fusion cage 702 in a superior-inferior direction. The secondengagement member 704 may move in the same direction or oppositedirections depending on the configuration. The system 700 may alsoinclude a support arm which extends from one arm of the fusion cage 702to the other arm of the fusion cage 702 in the lateral direction.

Referring to FIG. 8, a system 800 may include a fusion cage 802 and anengagement member 804. The fusion cage 802 may include a first member806 and a second member 808.

The first member 806 may include a first support portion 810. A surfaceof the first support portion 810 may interface with at least a surfaceof the first vertebral body.

The first member 806 may include a first channel to receive theengagement member 804 in an expanded position. The first channel mayinclude threads partially or entirely throughout its length.

The second member 808 may include a second support portion. A surface ofthe second support portion may interface with at least a surface of thefirst vertebral body.

The second member 808 may include a second channel to allow for passageof the engagement member 804. The second channel 816 may include threadspartially or entirely throughout its length.

The engagement member 804 may be inserted through the second channel andextends to the first channel causing the first member 806 to expand in asuperior inferior direction.

From a superior view the fusion cage 802 may be U-shaped with engagementmembers 804 on both arms of the U-shaped body. A second engagementmember may be positioned to cover the opening of the U-shaped body.

The second engagement member 818 may be employed to capture theengagement members 804 and lock them in place in the expanded position.The second engagement member 818 may include openings which may allowfor packing of graft material within the U-shaped body of the cage 802.

A surface of the first support portion and a surface of the secondsupport portion may include serrations or teeth. The serrations onsurface of the first support portion may be employed to engage the firstmember 806 with a surface of the first vertebral body. The serrations onsurface of the second support portion may be employed to engage thesecond member 808 with a surface of the second vertebral body.

Referring to FIG. 9, a system 900 may include a fusion cage 902 and anengagement member 904. The fusion cage 902 includes a first member 906and a second member 908.

The first member 906 may assume a U-shaped rectangular body from asuperior view. The first member 906 may include channel 916 forreceiving the engagement member 904. There may be one or many channels916 for receiving the engagement members 904. The channels 916 arepositioned at the corners of the rectangular body. The channel 916 maybe partially or fully threaded throughout its length.

The second member 908 may assume a U-shaped rectangular body from asuperior view. The second member 908 may include channel 924 forreceiving the engagement member 904. There may be one or many channels924 for receiving the engagement members 904. The channels 924 arepositioned at the corners of the rectangular body. The channel 924 maybe partially or fully threaded throughout its length.

The engagement member 904 may be a screw which may be turned causing thefirst member 906 and the second member 908 to extend away from oneanother in a superior inferior direction.

The engagement member 904 may include a middle portion 926 for rotationof the engagement member 904. The engagement member 904 may includethreads on its body on either side of the middle portion.

The engagement member 904 may allow expansion and retraction of the cage902. A second engagement member 926 may be employed to close off theopen end of the rectangular body and to maintain an expanded position ofthe fusion cage 902.

Referring to FIG. 10, a system 1000 may include a fusion cage 1002 andan engagement member 1004. The cage 1010 may assume a closed body with acentral opening from a superior view. More than one engagement member1004 may be present in the system 1000. The engagement member(s) 1004may be coaxial and may extend anterior to posterior through the centralopening engaging opposite sides of the cage 1002. The engagementmember(s) 1004 may adjust the fusion cage 1002 to provide lordosisadjustment.

An anterior view of the cage 1002 shows that the engagement member(s)1004 may be rotated by rotating a part of them which extends from theengagement member(s) 1004. This part of an engagement member 1004 mayinclude a drive socket and may be rotated to adjust the height of thecage 1002.

Referring to FIG. 11, a system 1100 may include a fusion cage 1102 andan engagement member 1104. The fusion cage 1102 may include a firstmember 1106 and a second member 1108.

The engagement member 1104 may be inserted in a medial lateral directionbetween the first member 1106 and the second member 1108. The engagementmember 1104 may be used to expand the cage 1102 by engaging between thefirst member 1106 and the second member 1108.

The engagement member 1104 may also include wings, barbs, ridges or thelike to prevent withdrawal of the engagement member 1104 from betweenthe first member 1106 and the second member 1108. Second engagementmembers may be used to fix first member 1106 and the second member 1108to the adjacent vertebral bodies.

Referring to FIGS. 12A-12B, a system 1200 may include a fusion cage 1202and an engagement member 1204. The fusion cage 1202 may include a firstmember 1206 and a second member 1208.

The first member 1206 may include a first support portion. The firstsupport portion may include a channel. The channel may extend in asuperior inferior direction along the first support portion. The channelmay include threads along its length either partially or entirely.

The second member 1208 may include a second support portion. The secondsupport portion may include a channel. The channel may extend in asuperior inferior direction along the second support portion. Thechannel may include threads along its length either partially orentirely.

The channels may be aligned in a collapsed position as well as in anexpanded position. The first member 1206 and the second member 1208 maybe engaged via the threaded channels.

When the threaded channels are actuated, the first member 1206 and thesecond member 1208 expand in a superior-inferior direction.

The first member 1206 may include an additional channel. The additionalchannel accommodates a second engagement member. The second engagementmember may be a spanner wrench. The spanner wrench may allow the cage1202 to be expanded.

The engagement member 1204 may also include features such as retractedspikes or bone engagement features which may be actuated after expansionof the cage. The spikes or bone engagement features engage the adjacentbone. The spikes or bone engagement features may be threaded.

Referring to FIG. 13, a system 1300 may be used for providing support totwo adjacent vertebral bodies. The system 1300 may include a fusion cage1302 and an engagement member 1304. The system 1300 may incorporate ananterior posterior fusion cage 1302. The fusion cage 1302 may be a keel.

The fusion cage 1302 may be actuated with the engagement member 1304.Once the fusion cage 1302 is implanted, the engagement member 1304 maybe actuated.

The system 1300 may include a second engagement member 1306 which may beprovided on the sides of the fusion cage 1302.

The actuation of the fusion cage 1302 by the engagement member 1304causes the second engagement member 1306 provided on the sides of thefusion cage 1302 to rotate outward into the bone space. The secondengagement member 1306 increases the fixation within the bone andresists direction of the expulsion forces.

The engagement member 1304 may be a cam that has the barb-like featurecontained within the cage 1302 in one position, and protruding from thecage 1302 when rotated 90 degrees.

Once the fusion cage 1302 is placed between two vertebral bodies, thesecond engagement member 1306 may be deployed into the vertebral body toresist pull-out of expulsion and help support or augment the engagement.

The fusion cage 1302 may be actuated via a screw mechanism, camwedge/taper, or other means. The second engagement member 1306 may becomposed of material that is flexible or slotted to be flexible, so thatonce deformed portions are deployed into the bone. The second engagementmember 1306 may be a helical blade that may be captured upon insertion,but once rotated it may protrude out of the cage 1302 into the bone.

Referring to FIG. 14, a system 1400 may be used for providing support totwo adjacent vertebral bodies. The system 1400 may include a fusion cage1402 and an engagement member 1404.

The fusion cage 1402 may include a first member 1406 and a second member1408.

The first member 1406 may include a support arm which may be a linearslide placed at a plethora of positions between the first member 1406and the second member 1408. The support arm 1412 may be extendingtowards the second member 1408 from the first member 1406

The first member 1406 may include a first channel to receive theengagement member 1404. The first channel may be partially or fullythreaded along its length. The first channel may have an obliqueorientation with respect to the first support portion.

The second member 1408 may include a second support portion which may bea linear slide placed at a plethora of positions between the firstmember 1406 and the second member 1408.

The second member 1408 may include a second channel to receive theengagement member 1404. The second channel may be partially or fullythreaded along its length. The second channel may have an obliqueorientation with respect to the second support portion.

The engagement member 1404 may be a jacking screw. The engagement member1404 may be partially or fully threaded along its length. The engagementmember 1404 may extend from the second channel to the first channel.

The engagement member 1404 may be actuated with a rotation nut towardthe second support portion.

The engagement member 1404 may engage the first member 1406 extendingthe support arm and increasing the space between the first member 1406and bottom second member 1408 to an expanded position.

Referring to FIG. 15, a system a system 1500 may be used for providingsupport to two adjacent vertebral bodies. The system 1500 may include afusion cage 1502 and an engagement member 1504. The fusion cage 1502 mayinclude a first member 1506 and a second member 1508.

The first member 1506 may include provisions for holding secondengagement members for engaging the first support portion with the firstvertebral body. The first member 1506 may include more than one secondengagement member.

The second member 1508 may include a second support portion. The secondsupport portion may interface a surface of the second vertebral body.

The second member 1508 may include provisions for holding secondengagement members for engaging the first support portion with the firstvertebral body. The first member 1506 may include more than one secondengagement members.

The engagement member 1504 may be disposed in between the first member1506 and the second member 1508.

The more than one second engagement members may be provided at obtuseangles with respect to the first support portion to engage with theadjacent vertebral bodies.

Multiple drive features may be employed as described in the previousembodiments to drive the engagement member 1504 to expand the spacebetween the first member 1506 and the second member 1508.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. It isappreciated that various features of the above described examples andembodiments may be mixed and matched to form a variety of othercombinations and alternatives. It is also appreciated that this systemshould not be limited simply to fusion cages. As such, the describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

The invention claimed is:
 1. A system comprising a spinal fusion cageand at least one engagement member; the fusion cage comprising: a firstmember comprising a first support portion configured to interface withat least a surface of a first vertebral body, wherein the first memberdefines a first channel; and a second member comprising a second supportportion configured to interface with at least a surface of a secondvertebral body, wherein the second member defines a second channel,wherein, the first member and second member are configured to beoperable to assume a collapsed position; the first member and secondmember are configured to be operable to assume an expanded position; thefirst channel and the second channel are offset in the collapsedposition; and the first channel and the second channel are aligned inthe expanded position; and the engagement member configured to be atleast partially received by the first channel and the second channel,wherein the engagement member is also configured to simultaneouslyengage all of the first member, the second member, and neighboringvertebrae; wherein the first channel is obliquely oriented with respectto the first support portion of the first member, and the second channelis obliquely oriented with respect to the second support portion of thesecond member.
 2. The system of claim 1, wherein each of the firstchannel and the second channel is at least partially threaded, and theengagement member comprises a body, wherein at least a portion of thebody is threaded.
 3. The system of claim 1, wherein, the first membercomprises at least a pair of support arms, wherein each of the supportarms extend from the first support portion towards the second supportportion; the second member comprises at least a pair of support arms,wherein each of the support arms of the second member extend from thesecond support portion towards the first support portion; and at leastone of the pair of support arms of the first member is configured todisposed between the pair of support arms of the second member in thecollapsed position.
 4. The system of claim 3, wherein at least one ofthe support arms of, one of the first member and the second memberdefines at least one slot, and at least one of the support arms of theother comprises a key member, wherein the slot is configured to receivethe key member at least in the collapsed position.
 5. The system ofclaim 3, wherein, each of the support arms comprises an interfacesurface, wherein, the interface surface of the support arms of the firstmember faces away from the first support portion; the interface surfaceof the support arms of the second member faces away from the secondsupport portion; and in the expanded position, at least a portion theinterface surface of each of the support arms of the first memberinterfaces with at least a portion of the interface surface of thesupport arms of the second member.
 6. The system of claim 3, wherein,the first member comprises a third support arm extending between thefirst support portion and its support arms; the second member comprisesa third support arm extending between the second support portion and itssupport arms; and at least in the expanded position, the first memberand the second member define a space accessible through a single plane.7. The system of claim 1, wherein, the engagement member comprises, afirst blade member, a first neck member, a first beam member, a secondbeam member and a beam connecting member, wherein the first blade memberis configured to be inserted into the first vertebral body, the firstneck member connects the first blade member and the first beam member,the beam connecting member connects the first beam member and the secondbeam member; the first channel defines a first neck receiving portion, afirst beam member receiving portion and a beam connecting memberreceiving portion, wherein the first neck receiving portion isconfigured to receive at least a portion of the first neck, the firstbeam member receiving portion is configured to receive the first beammember, and the beam connecting member receiving portion is configuredto receive a first portion of the beam connecting member; the secondchannel at least defines a second beam member receiving portion and abeam connecting member receiving portion, wherein the second beam memberreceiving portion is configured to receive the second beam member, andthe beam connecting member receiving portion is configured to receive asecond portion of the beam connecting member; and the first beam member,the second beam member and the beam connecting member are configuredsuch that when the engagement member is received by the fusion cage inthe expanded position, the first beam member, the second beam member andthe beam connecting member prevents the first member and the secondmember from moving away from each other.
 8. The system of claim 7,wherein, the engagement member further comprises, a second blade memberand a second neck member, wherein the second blade member is configuredto be inserted into the second vertebral body and the second neck memberconnects the second blade member and the second beam member; and thesecond channel further defines a second neck receiving portion, whereinthe second neck receiving portion is configured to receive at least aportion of the second neck.
 9. The system of claim 8, wherein, the firstmember comprises at least a pair of support arms, wherein each of thesupport arms extend from the first support portion towards the secondsupport portion; the second member comprises at least a pair of supportarms, wherein each of the support arms of the second member extend fromthe second support portion towards the first support portion; the firstchannel is defined in one of the support arms of the first member andthe first support portion; and the second channel is defined in one ofthe support arms of the second member and the second support portion.10. A method, comprising: positioning a first member and a second memberin a space defined between two adjacent bodies, wherein the first memberand the second member are configured to be in a collapsed position;moving at least one of the first member and the second member such thata first channel defined in the first member and a second channel definedin the second member, which are offset in the collapsed position, arealigned; and inserting an engagement member into the first channel, thesecond channel, and neighboring vertebrae; wherein inserting theengagement member into the first channel and the second channelcomprises inserting at least a portion of the engagement member into atleast one of the two adjacent bodies; and wherein inserting theengagement member comprises applying torsion force to the engagementmember for enabling insertion.
 11. The method of claim 10, whereinaligning the channels from a state where the channels are offsetcomprises, moving at least one of the first member and the second memberalong a first axis, and thereafter, moving at least one of the firstmember and the second member along a second axis, wherein the first axisand the second axis intersect.
 12. The method of claim 10, whereininserting the engagement member into the first channel and the secondchannel comprises inserting the engagement member along an axis that isoblique to a plane of a surface of the first channel interfacing one ofthe adjacent bodies.
 13. The method of claim 10, wherein inserting theengagement member into the first channel and the second channelcomprises inserting the engagement member along an axis that is parallelto a plane of a surface of the first channel interfacing one of theadjacent bodies.